Drought-Induced Transposon Expression Reveals Complex Drought Response Mechanisms in Brassica napus

Manyi Chen¹Dan Luo²Hanzuo Kong¹Yan Lv²Chunsheng Li³Yongguo Zhao^1*Qian Huang^4*Guangyuan Lu^1*

• ¹Guangdong University of Petrochemical Technology, Maoming, China
• ²Chinese Academy of Agricultural Sciences (CAAS), Beijing, Beijing Municipality, China
• ³Hubei Engineering University, Xiaogan, Hubei, China
• ⁴Zhejiang University, Hangzhou, Zhejiang Province, China

Transposable elements (TEs) are abundant elements in plant genomes. While current research primarily focuses on the effects of TE insertions and deletions on plant phenotypes, there is limited exploration of TE transcription and their potential biological functions. This study systematically analyzed TE expression under drought stress during seed development using RNA-seq data from the wild-type (WT) and BnaABI5 CRISPR-edited (mutant) lines of Brassica napus. The genome of B. napus contains a total of 212,800 TEs, of which 17,547 are capable of producing transcripts. These transcripts include 15,808 protein-coding TE transcripts and 1,739 long non-coding (lnc) TE transcripts. Among the protein-coding TE transcripts located in intergenic regions, 65 are transposase genes. In contrast, the remaining 860 transcripts likely represent novel genes evolved from transposon regions, such as those involved in monocarboxylic acid metabolic processes. A total of 128 protein-coding (including 5 transposases) and 37 lnc TE transcripts were found to be involved in rapeseed seed germination responses to drought stress.Notably, the lnc TE transcripts MSTRG.108925.4 and MSTRG.109003.7 may contribute to drought stress responses during seed germination by regulating the PHD finger protein ALFIN-LIKE 1 (BnA10g0418090). These analyses of TE transcription provide new insights into TE function and transcriptional characteristics, offering resources for identifying additional drought-resistant genes and lnc RNAs in rapeseed.